Dariusz Pyka

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• Ph.D. Eng.
• Head Dynamics and Modelling Division at Wrocław University of Science and Technology

The rapid development of 3D printing technology has enabled its application in many fields, including dentistry. One of the key applications is temporary prosthetic restorations on dental implants, used during the osteointegration process. These restorations provide functionality and aesthetics, but their durability under oral conditions exposed to...

The article presents an experimental and numerical study on the effectiveness of an additional shield mounted under the vehicles in reducing the penetration capability of the scattered mines, using the example of the MN-123 mine. For this purpose, the formation of the EFP (explosive formed penetrator) was analyzed for the classic scattered mine sys...

The authors of this study focused their research on developing cap geometries for the FibroScan® elastograph (FibroScan, EchoSens, Paris, France) measuring head aimed at a non-invasive assessment of liver condition for transplantation using a pig animal model. Numerical models were created to simulate the propagation of a mechanical wave through a...

This study focuses on the development and evaluation of the OrthoNail hybrid intramedullary implant for lower limb lengthening in patients requiring significant skeletal reconstruction. The implant addresses the challenges in load-bearing during rehabilitation, providing a robust solution that is capable of supporting physiological loads. Mechanica...

This study investigates the combustion of hydrogen in supercritical gas turbines, emphasizing the optimization of combustor design through computational fluid dynamics (CFD) simulations. Key parameters analysed include the number of oxygen inlets, operating pressure, excess working fluid in oxygen inlets, power output, and the use of different work...

This article presents a numerical optimization of an explosively formed charge insert based on an anti-bullet, anti-tank MPB mine (pl. mina przeciwburtowa, eng. anti-side mine). For this purpose, first of all, the chemical composition and microstructure of the currently used EFP inserts and the target material - armour-piercing steel - were analyze...

This study investigates the mechanical properties and biocompatibility of eight commercially available filaments tailored for Fused Deposition Modeling (FDM) additive manufacturing. Test specimens were fabricated using original PRUSA MK4 printers, with ten samples from each selected polymer. Mechanical evaluations through static tensile and three-p...

In this study, the authors performed a strength analysis of seven groups of commercially available materials based on SLS incremental technology. Test samples were made with Original PRUSA SL1S printers, with 10 samples of each type from 7 resins selected for testing. The tests were carried out on an MTS Bionix machine in a static tensile test, dur...

The tests of resistance to dynamic impact with shaped charge (ŁK) were carried out on a homogeneous armor plate made of Armox 370T Class 1 steel, commonly used in the production of ballistic shields. The chemical composition of the steel was determined in spectrometric tests using a spark discharge spectrometer S1 MiniLab 150 by GNR INDIA and confi...

To design effective energy-absorbing shields made of modern composite materials (e.g., fibrous composite panels), it is necessary to use deformable materials whose important feature is the largest possible dissipation of impact energy. Rheological properties of these materials differ significantly from dissipative and elastic properties described b...

The shock wave resulting from the explosion process is the main burden on the technical infrastructure facilities or people in contact with the epicentre of the high explosive (HE). The article presents the tests of EN C45 steel pipe of 10 mm thickness buried beneath the earth as a result of the impulse load of the detonation wave of the explosive...

In this study, the authors analyzed modern resin materials typically used for temporary reconstructions on implants and manufactured via 3D printing. Three broadly used resins: NextDent Denture 3D, NextDent C&B MFH Bleach, and Graphy TC-80DP were selected for analysis and compared to currently used acrylic materials and ABS-like resin. In order to...

This paper presents the possibility of using additional ballistic shields based on composite materials, which are applied to the body of a passenger car. A ballistic laminate made of Twaron T 750 aramid fabric with 5 mm thick and 2 mm thick magnetic foil was used. In the first stage, the mechanical parameters of the tested ballistic laminate system...

This article analyzes the composition and distribution of chemical elements in friction films and their effect on the tribological properties of the self-lubricating, high-temperature antifriction composite based on EP975 powder nickel alloy with CaF 2 solid lubricant. Analysis of the chemical elements by energy-dispersive spectroscopy (EDS) showed...

The authors of this paper focused their attention on developing numerical models of mechanical wave propagation along human tissue as a result of the application of the measuring head of the FibroScan® elastograph. The FibroScan® diagnostic device is used for diagnostic testing of liver fibrosis and steatosis. This examination is carried out using...

Multi-layer fabrics are commonly used in ballistics shields with a lower bulletproof class to protect against pistol and revolver bullets. In order to additionally limit the dynamic deflection of the samples, layers reinforced with additional materials, including non-Newtonian fluids compacted by shear, are additionally used. Performing a wide rang...

This article is devoted to research of the tribosynthesis mechanism of antifriction films and their influence on the functional properties of antifriction composites based on copper alloyed with nickel and molybdenum with the CaF 2 solid lubricant additions for operation at rotation speeds of 3,000–7,000 rph and increased loads of 3.0–5.0 MPa in ai...

The main aim of the work was the experimental and numerical analysis of the energy absorption/dissipation capabilities and failure mechanisms of novel hyper-elastic target material intended for ballistic applications including layers of composite armors, projectile catching systems and anti-ricochet layers covering walls of shooting ranges, ballist...

Effectiveness of simplified modeling methods of ballistic inserts containing high-strength para-aramid fabrics under projectile impact condition was analyzed in the article. Various types of experimental tests including material characterization and ballistic impact were carried out in order to define and to validate numerical models of the individ...

In this paper, the subject of the analysis is Rotinger High Performance brake disc, characterized by increased thermal resistance, which is a result of adequate design and material solutions. However, despite declared performance, the analyzed discs suffered accelerated wear over a period of about 20 months. The aim of this study was to assess the...

The study aramid fabrics of Twaron T750 type loaded in quasi-static punching and impact loading tests were tested. The scope of these works was carried out in the form of piercing with a non-deformable steel penetrator with a semi-spherical tip, moving at a constant low speed and on the drop impact test and firing the aramid fabric with a 9 × 19 mm...

This article presents the tests of EN C45 steel as a result of the impulse load of the detonation wave of the explosive charge. This process was carried out on a specially prepared test stand using a 75 g Tri-Nitro-Toluene (TNT) drilling cartridge. Two series of tests were carried out with the explosive charge placed in direct contact with the samp...

This article presents an analysis of the effectiveness of available numerical techniques in mapping the characteristic behavior of ballistic ceramics under projectile impact conditions. As part of the work, the ballistic tests were performed on the layered ceramic/steel composite armor and tested with the 7.62 × 39 mm, armor-piercing incendiary (AP...

In recent years, hybrid composite materials are of increasing interest during the search for new materials to be used as ballistic barriers (shields) and kinetic energy absorbers. The main objective of this study is to test the energy absorption capacity of Zn-Al alloys filled with various polymer materials (epoxy resin, polyurethane resin and sili...

Finite element modeling of ballistic impact of inserts containing titanium structures were presented in the article. The inserts containing an additional layer made using additive manufacturing technology were analyzed. The layer was created from repetitive elements made without connections (adjacent cells were inseparable). Four variants of printe...

This paper presents the results of research on ballistic panels made of polymer–matrix composites (PMCs). The analysis covers two types of composites produced by the authors based on high-density polyethylene (PEHD) and polypropylene (PP) reinforced with aramid fabric. Ballistic tests were carried out with the use of two types of projectile: 0.38 S...

In this paper, the authors presented an analysis of the strengthening of the cumulative jet by the appropriate formation of the detonation wave front acting under the influence of high pressure on the liner. The analysis of the Polish ŁK cumulative charge was carried out using numerical methods in the ABAQUS program. Simulation studies were carried...

The friction behavior of the formed antifriction films and their effect on the functional properties of the composite based on the powder nickel alloy EI929 with solid lubricant CaF2 at high temperatures was investigated. An antifriction film was formed on the contact surfaces during the friction process. Such a film was the result of the interacti...

The paper presents the results of studies on the effects of shooting composite materials produced by pressure infiltration with the EN AW-7075 alloy as a matrix and reinforcement in the form of preforms made of α-Al2O3 particles. Composite materials were made with two reinforcement contents (i.e., 30% and 40% vol. of α-Al2O3 particles). The composi...

The aim of this work was to evaluate the influence of the matrix type and the number of reinforcement layers on the punch of the aramid laminates. The samples were tested under laboratory conditions and in a ballistic test. Two series of aramid laminates were produced with differing types of polymer matrix. The epoxy resin (EP) and the styrenebutad...

The work presents the concept of a gun barrel reinforced with the continuous filament. The barrel’s vulnerability to vibration and bending during shooting significantly affects the accuracy of fire. The phenomenon of vibrations of the barrel is compensated by its mass and such parameters as the maximum pressure acting in its front part, i.e. the ca...

The paper discusses the impact of explosively formed projectiles (EFP) on the process of penetration of armor elements. The protective abilities of homogeneous armor plates and their structure as a result of fast-changing phase transitions have been analyzed. The phenomenon of exposing the analyzed energy-absorbing shield to the EFP impact was also...

The authors simulated the piercing of a loose aramid fabric. The analysis was carried out in the ABAQUS environment with the use of the Explicit method. The fabric was modeled in two ways: the first one as a surface, with the parameters and nature of aramid fibers considered, while the second as single bands in the fabric. The qualitative and quant...

The phenomena found in the UKM-2000P machine gun barrel during the firing were investigated. The aim was to evaluate how the change in the center of the mass of the projectile being fired affects the occurring barrel vibrations. Numerical simulations were performed in the ABAQUS program, and then the results were compared with the experimental resu...

ABSTRACT The article contains a comparison of selected numerical methods describing the structure of polymer composite. This work focuses on different FEM modeling methods using homogenization of composite material parameters. The estimation is based on comparing visual results of real ballistic test and numerical simulations. The main goal of this...

This work discusses the impact consequences of Explosively Formed Projectiles (EFP) on the process of armor penetration. Based on the example of piercing shields made of armor steel ARMOX 370T with anti-vehicle mine of MPB type to verify the effectiveness of EFP charge. The influence of the projectile on the armor wall was analyzed on the basis of...

The work presents the research conducted on the impact resistance of newly developed metal-ceramic composites with aluminum matrix on firing with 5.56 × 45 mm caliber intermediate ammunition. For this purpose, materials based on AC-44200 alloy reinforced with Al2O3 particles were made using the squeeze casting method. The ballistic resistance was c...

This paper presents numerical examination of cermet-type composite material subjected to impact loads. The base material was Aluminum 44200 matrix material, and materials with 20% and 40% digix trioxide as an additive. Using the ABAQUS software, homogenization of the Representative Volume Element material was performed and then subjected to dynamic...

The paper analyzes the issues relating to the applicability of innovative material systems for flexible composite armors. The authors made several samplings of aramid fibers (Kevlar 49) by replacing the epoxy resin base, which is often described in the literature, with the thermoplastic matrix - polyethylene (HDPE) and polypropylene (PP). The sampl...

For protection against projectiles with higher impact speed (up to 1000 m/s) a type of a ballistic sandwich shield can be used—which is a monolithic combination of ballistic laminates with additional materials, typically hard layers made of ceramic in the form of plates or spheres of oxides, carbides and nitrides. The authors of this paper, by usin...

This paper concerns the ballistic resistance of hybrid composite shields. The analysis covers three types of two-layer composites. The first shield layer were plates of tungsten carbide (WC), ceramic balls Al2O3 (aluminum oxide 92) or steel balls (100Cr6 steel) embedded in a polymer matrix. The second layer was a laminate consisting of 10 layers of...

Research for innovative composite material solutions for impact absorbers is focused on the analysis of their ability to absorb impact energy. For this purpose, aramid fiber laminate with DCPD resin matrix was prepared. Laminate samples were tested on the drop test and were subjected to ballistic loads. The laminate structure was modeled with ABAQU...